In the “Build” tab of the “Preferences” window, you can set a default compression format for each platform your project is targeting. You can then optionally set specific assets to override that format with a different format in the assets browser. To do so, just select the asset (or folder of assets) whose format you want to change, and click where it says “Click to add a custom platform encoding setting”.

Incidentally, it’s totally fine for assets in the same bank to have different compression formats, if that would be of benefit to your project.